Town's reserves lost 3-2 to a strong Spurs second string on Wednesday night at Portman Road, but might have got a draw had Dean Bowditch scored a penalty.
The Blues went ahead through Nabil Abidallah, the Tottenham keeper Lars Hirschfeld making a pig's ear of his shot.
Bobby Zamora equalised but then Matt Bloomfield out Town back in front.
Zamora again equalised before Spurs' Portuguese summer signing Helder Postiga hit the post.
Bowditch was tripped in the area by O'Donoghue but the striker's spotkick was saved by Hirschfeld.
The visitors went straight up the other end and netted a winner through Stephane Dalmat.
For Town Nabil Abidallah impressed along with left-back Erkan Okay. It was cruel for the side to lose when up against many more illustrious opponents.
Town: Marshall, Mitchell, Okay, Murray, Collins, Nash, Abidallah (Atay 80), Bloomfield, Morrow, Bowditch, Westlake.